At present, a communication system generally uses a channel encoding method to improve reliability of data transmission and ensure communication quality. A Polar code is a linear block code that can achieve Shannon capacity and has low encoding complexity. An encoding process of a Polar code is x1N=u1NGN., where GN.=BNF⊗n, N is a code length and N=2n, n is an integer not smaller than 0,
      F    =          [                                    1                                0                                                1                                1                              ]        ,and BN is a transposed matrix. A decoding method corresponding to the Polar code is SC (successive-cancellation, successive cancellation).
In the prior art, after an information bit is checked according to a CRC (Cyclic Redundancy Check, cyclic redundancy check) check code, the information bit and the CRC check code are encoded according to the Polar encoding method and then, transmitted to a destination end. The destination end may perform decoding by using an SC decoding method. The SC decoding is decoding according to the encoding method of the Polar code, which achieves very good performance when the code length N is very large.
In the process of implementing the encoding and decoding mentioned above, the inventor finds that the prior art has at least the following problems: After the information bit is checked by using CRC, the information bit and the CRC check code are encoded by using the Polar encoding method and then, transmitted to the destination end, where the destination end uses the SC decoding method; and because SC decoding quality of the SC decoding method is poor when the code length N is small or medium, the decoding performance is decreased, which reduces user experience.